The objective of the project is to further our understanding of the role played by signalling pheromones in the regulation of social behavior in rodents. In particular, we plan to explore both maturational and experimental determinants of the responses by rodents to pheromones in four social contexts: namely, mating, mother-young interactions, feeding behavior, and withdrawal responses evoked by stress or alarm signals. In three experiments, we will observe the effects of pheromones upon the rodents' movements in space (i.e., both tactic and kinetic responses). In another experiment, we will observe the effect of a pheromone upon a consummatory response (i.e., feeding behavior). The four experiments are: (1) the responses of sexually native adult male rats to the odors from receptive versus non-receptive females, (2) the responses of rat pups and their mothers to nest odors, (3) the effect of conspecific body odor upon feeding behavior, and (4) the responses of immature and mature mice to stressed versus nonstressed conspecifics.